that blue light was not responsible for the rate of photosynthesis.

The Control Unit (CU) was designed to support twenty HEX units, four sets of controls to regulate RGB independently on five HEX units. By specification, the Norlux HEX array has a maximum input voltage of 11.7 V and 1.5 A of input current (200 mA per HEX). A circuit was developed where a single potentiometer controls the output from each of the red, blue and green LED arrays in 5 separate HEX units. A single circuit that controls one color in five arrays is shown in Figure . This circuit consists of a standard 25 A power supply delivering 13.8 VDC to a common bus that feeds an LM317 voltage regulator. Voltage to the array is modulated by a potentiometer as well as an in-line switch. A 1 K ohm power resistor is placed in the circuit as a current limiter. The voltage regulator and the LEDs require a stable DC input. Input and output capacitors were added to minimize ripple for improved transient response. A more stable voltage waveform assures consistent output. This simple configuration is repeated for each color. There are twelve individual circuits in the control unit, each controlling R, G, or B in each of four light arrays.

Effect of different colors of light on the rate of photosynthesisThe effect of different lights on plant growth: incandescent light, fluorescent light, sunlight and black light.

15/11/2016 · Firstly, your premise is incorrect

This process is called photosynthesis. Temperature, carbon dioxide concentration and light intensity are factors that can limit the rate of photosynthesis.

Photosynthesis happens best in blue light

This process is called photosynthesis. Temperature, carbon dioxide concentration and light intensity are factors that can limit the rate of photosynthesis.

That’s because chlorophyll is green

While phytochromes and cryptochrome effects are salient as stem growth inhibition after days of growth in constant light, other rapid responses involve other light sensors and can be measured on the order of minutes rather than days. Contrary to the effects of red and blue, a short single pulse of green light stimulates rapid elongation of the hypocotyl in the dark-grown seedling []. The response persists in all photomorphogenic mutants, it occurs when plants are grown in constant dim red light, and growth promotion is the opposite of what occurs when seedlings are irradiated with red or blue light. This evidence renders it difficult to conveniently ascribe this response to any of the known light sensors, and it is likely being mediated by a separate green-sensitive transduction pathway. Figure , shows the results of 20 independent seedlings treated with green light from the Norlux HEX arrays, compared to previously published data []. Seedlings irradiated with a short, single pulse of green light begin to grow rapidly within 15 min, attaining 140% of their dark rate before growth rate declines to dark levels after an hour. The results are highly similar to published findings, again indicating that Norlux HEX arrays are a suitable alternative to other LED or fluorescent light sources.

Is photosynthesis possible in yellow light? | Biology

Green light is also used in photosynthesis, as can be seen from the leaf action spectrum (FIG. 2). It has been established that green light drives photosynthesis more effectively than red or blue light deep within the leaf (Terashima et al. 2009). Further, the insects used in greenhouses as pollinators and biological control agents see best in the green and ultraviolet regions of the spectrum. More interestingly, changes of even 10 nm in the peak wavelength of green light can have dramatic effects on the growth of plants such as lettuce (Johkan et al. 2012).

photosynthesis notes - Biology Junction

As noted by McCree (1972a), neither PPFD (quantum flux density) nor YPFD (irradiance) are perfect measures of photosynthetically active radiation in that both systematically overestimate the effectiveness of blue light relative to red. As can be seen from FIG. 3, the error is greater for YPFD, which explains why PPFD measurements are preferred by horticulturalists. Nevertheless, they are useful in that they are independent of any particular plant species, and they can be measured both in the laboratory and in the field using a radiometer with a spectrally-calibrated quantum sensor such as the LI-190SA with LI-COR ().

Research activities by this research group at the University of Florida center on developmental transitions, namely the progression of seedling growth between dark and light environments as well as the vegetative/floral transition. These processes are all controlled by a well-defined set of photosensors, responsive to the various portions of the spectrum. The ability to independently control specific wavebands makes it possible to assess how independent light sensing systems integrate environmental information to tailor the developmental response in question. Experiments are performed on small seedlings or throughout the life cycle of Arabidopsis thaliana plants, so an optimal light bank would be self contained, relatively small, and easily moveable. With these considerations in mind, the tunable RGB banks were developed. Each tunable RGB bank consists of 5 HEX arrays (Figure ), 150 total dies, where the red, blue and green dies are independently adjustable. 20 HEX arrays allow for 4 independent light banks that may be run simultaneously with equal spectral output to irradiate a large area (~1.0 × 0.25 m). Alternatively, each may be independently controlled to illuminate up to four separate spectral quality/quantity conditions at the one time. Two separate photoperiods may be controlled using two independent power supplies and timers.

As a reminder, photosynthetically active radiation (PAR) does not consider the spectral response of plants (FIG. 3); it simply represents the number of photons (quanta) per unit area per second within the range of 400 to 700 nm. With the availability of color-tunable LED modules for greenhouse lighting, horticulturalists will likely want to experiment with different SPDs for specific crops and flowering plants, as well as both the directionality and daily timing (photoperiods) of the luminaires. Regardless, being able to convert predicted and measured illuminance values to PPFD values for common light sources will certainly ease the communication problem between lighting designers and horticulturalists.

Why the rate of Photosynthesis is higher in red light …

Record or report findings.Rate of photosynthesis (measured by ET50, time it took for 50% of the leaf disks to float up)Color of light (wavelength of light)Light intensity, temperature, bicarbonate concentration (0.2%), depth of bicarbonate solution, direction of incoming light, pH, amount of soap, size of leaf disk, type of plantTen trials for each color, however for each trial, a few disks did not float up.

Botany: Why is photosynthesis maximum in red light? …

Green or yellow light will have the slowest rates of photosynthesis because they are reflected by the pigments in the plant.MATERIALSPROCEDUREPROCEDURAL FACTORSINDEPENDENT VARIABLEDEPENDENT VARIABLECONFOUNDING VARIABLESCONTROL GROUPREPLICATIONTABLEGRAPHDESCRIPTION & ANALYSISSOURCES OF ERROR AND IMPROVEMENTSIn this lab experiment, the team examines how the rate of photosynthesis is affected by different light colors in the leafs.